High-frequency heated mold for shoe soles



Nov. 15, 1949 J. GREG@ HIGH-FREQUENCY HEATED `MOLD FOR SHOE SOLES 4 Sheets-Sheet l Filed Aug. 11, 1945 v INVENTOR Jbl? @re ATTORNEY.

Nov. l5, 1949 J. GREGG 2,487,866

` HIGH-FREQUENCY HEATED MOLD FOR SHOE SOLES Filed Aug. 1l. 1945 4 Sheets-Sheet 2 INVENTQR .fon Greig BY 2603- ATTORNEY 1V I l; 1 Q Jdf Y Om.,

. J- GREGG l HIGH-FREQUENCY HEATED MOLD FOR SHOE SOLES Nov. '15, 1949l 4 Sheets-Sheet 5 Filed Aug. l1, 1945 INVENTO J0?? greyy QQNY.

Nove 15, 1949 L GREG@ HIGH-FREQUENCY HEATED MOLD FOR sHoE soLEs 4 Sheets-Sheet 4 Filed Aug. l1, 1945 .fo/7 Gr (gf iB. 1:/

ATTORNEY.

Patented Nov. 15,n 1949 HIGH-FREQUENCY HEATED MOLD FOR SHOE SOLES Jon Gregg, New Hope, Pa.

Application August 11, 1945, Serial No. .610,262

8 Claims.

This invention relates to molding devices. It is particularly directed to a mold for molding shoe soles, rugs, fabrics, mats, or other articles.

An object of this invention is to provide a mold of the character described which may be used for molding articles which are heated by the use -of high or radio frequency current.

Another object of this invention is to provide a mold having means to impose on the article to be molded both vertical and horizontal pressure during the molding operation.

A further object of this invention is to provide a mold of the character described comprising a Vbody made of non-conductive, heat resistant, di-

vbody of ceramic material formed with a cavity, a

bottom member for the cavity made of metal, a ram for the top of the cavity made of metal for applying vertical pressure to the molded material, and a sliding member on the body for applying horizontal pressure to the molded material, the construction being such that the vertical ram and the sliding part are self-locking.

A further object of this invention is to provide a mold of the character described having a floating bottom electrode at the bottom of the mold cavity which will permit good contact with the bus bar of a high frequency apparatus and which can be used to eject the sole or molded article from the mold, and which will equalize pressure on the sole or other molded article.

Still a further object of this invention is to provide a mold of the character described in which the top and bottom electrodes are so arranged that the high frequency waves will pass directly through the mold cavity, the mold being so constructed that no vertical metal parts penetrate down to a depth greater than the bottom surface of the rain from the upper surface of the mold nor project higher than the top surface of bottom member from the lower surface of the mold.

Yet a further object of this invention is to pro- .face I9.

described which shall be easy to open and close or interlock, and which shall be relatively inexpensive to manufacture, and yet practical and efficient to a high degree in use.

Other objects of this invention will in part be obvious and in part hereinafter pointed out.

The invention accordingly consists in the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter described, and of which the scope of application will be indicated in the following claims.

In the accompanying drawing, in which is shown various possible illustrative embodiments of this invention,

Fig. 1 is 'a top plan view of a mold embodying the invention;

Fig. 2 is a front edge View thereof;

Fig. 3 is a cross-sectional view taken on line 3 3 of Fig. 1;

Fig. 4 is a cross-sectional view taken on line 4 4 of Fig. 1;

Fig. 5 is a cross-sectional view taken on line 5 5 of Fig. 1;

Fig. 6 is a cross-sectional view taken on line 6 6 of Fig. 1;

Fig. 7 is a top plan view of a mold embodying the invention and illustrating a modified construction;

Fig. 8 is a front edge view thereof;

Fig. 9 is a cross-sectional view taken on line 9 9 of Fig. 7;

Fig. 10 is a cross-sectional View taken on line Ill-Ill of Fig. 7 and Showing the cover plate opened up;

Fig. 11 is a cross-sectional View taken on line Il II of Fig. 1;

Fig. 12 is a partial enlarged vertical cross-sectional Viewr of the mold; and

Fig. 13 is a transverse, cross-sectional view of a. mold embodying the invention and illustrating 'a modication comprising a double mold cavity.

Fig. 14 is a fragmentary elevational cross sectional view of a modification.

Referring now in detail to the drawing, l0 designates a mold embodying the invention. The

Vsame comprises generally a body I I, a sliding part I2, a bottom plate or electrode I3, and a top plate and ram I4. The body iI is made of electric insulating, heat resisting material, such as ceramics, and may be generally of prismatic shape.

.It has a bottom surface I5, a top surface I6, end surfaces I1, a front surface i8, and a rear survide a compact, durable mold of the character Said body Il is formed with a central through of surface 22 is a horizontal shoulder 23 extending i outwardly therefrom and disposed below surface Zla. of shoulder 23 is a vertical surface 25 extending to a point above the horizontal surface 2Ia. 'If-he surface 25 extends all around from one edge 2 Ib to the other edge 2 Ib.

Extending upwardly from surface 25 is an up,- wardly and outwardly tapered surface 26 which also extends all around from one surface ZIE to the other surface 2lb. The sliding part I2 when in operational position on the mold, has a front surface 2l flush with surface I8. It has end surfaces 28 adapted to slidably contact the sur;- faces 2lb. It has a bottom surface 29 having sliding contact with surface Zia. of part I2 is a surface 3@ complementary to sur face 25, and a surface 3l complementary to surface 26. The top surface 32 of part I2 is flush with the top surface i5 of part I I.

Mounted in body Il is said bottom plate or electrode I3. It comprises a portion I3a slidably fitted within opening portion 22 and it is formed at the top with a horizontal integral flange lh extending all around and adapted to abut the shoulder 23 of body II. The outer edge I3 c of flange I3b has sliding contact with the. lower portion of surface 25. When the flange Iiib. contacts shoulder 23, the lower surface I3d of; plate I is disposed somewhat below the lower surface I5 of body II and the upper surface I 3e is flush with surface 2Ia. When the electrode. I3 is pushed upwardly to a point where the lower surface I3@ thereof is flush with said sur-face. I5, then the upper surface I3e of the electrode is somewhat higher than surface 2 Ia.

The top member i4 is a combination cover plate and ram. It comprises a portion lila contacting the upper surface I6 of the body. Extending rearwardly from portion 14a are a pair ofi parallel arms 4E likewise adapted to Contact the upper surface i6. Fixed to the upper surface of the rear ends of said arms are hinge sleeves 4I formed with through openings 42.

Means is provided to pivotally connect member I4 to body ll. To this end said body is formed in its upper surface and on opposite. sides of each sleeve 4I with a pair of blind holes. In each hole is a sleeve 44 formed with an internal screw threaded opening 45,. The sleeve 4 4 may be embedded in the holes by lead or any other suitable material. Screwed to each opening 45 is a hinge member 4t. Each member 45 has a screw threaded stem 41 screwed into the hole 45. It is formed at its upper end witha head 48 having a through opening 49. Theopenings 43 register with the openings 42. Extending through said openings 42, 49 are pivot pins 5B. Extending from the plate portion I4a toward the front of the mold, are a pair of parallel arms 5 2 adapted to overlie the sliding partA I2. Arms 52 may each be formed with a rectangular slot or opening 54 adjacent their outer ends, for the purpose hereinafter appearing.

Extending from the underside of plate Ida, is an integral ram 60 adapted to project down into Extending upwardly from the outer edge At thev rear Cil the opening 20 when the plate I4 is swung down wardly. The ram 66 has a downwardly and inwardly tapered side wall 6l extending all around and having the shape of the surfaces 2t, 3|.

Said ram has an undersurface 62 spaced above the top surface I3e of the bottom plate I3 and forming therewith a mold cavity 63. The height of the mold cavity 53, when the bottom terminal I3 is moved upwardly to bring surface I3d flush with bottom surface I5, is of a depth somewhat less than the height of the finished molded article; When the. terminal I3 is in the position shown in Fig. 4, the height of the cavity is substantially equivalent to the height of the molded article.

The ram B is formed on its underside, all around the peripheral edge thereof with a shallowrecess 64. Adjacent the outer edge of the recess G4 is an outwardly and downwardly inclined surface 55 forming a knife edge 65 at the lower end of the peripheral edge of the ram and lower than surface 62, the purpose of which will appear hereinafter. Extending downwardly from the bottom of the recess 64 are a plurality of spaced cleats or pins 51.

Means is provided to guide part I2 within groove 2l. Tothis end the upper surface of body II is formed, on each side of groove 2i, with a pair of spaced aligned blind openings 'I parallel to surfaces 2lb. Embedded within each opening is a sleeve 'il formed with a screw threaded through opening. Said body II is furthermore formed with a cylindrical blind opening 'I2 between each pair of openings l0, for the purpose hereinafter appearing.

Fixed to the upper surface of the body II are a. pair of similar, symmetrically disposed guide plates 'E3 overlapping part I2 for retaining said part on surface 2 Ia. Plates 'I3 are aixed to body II by means of screws 'I5 passing through openings in the plate and screwed within the screw threaded sleeve 1I.

Means is providedto limit sliding movement of part I2 relative to body II. To this end, each of plates 'i3 is formed with an opening 'i6 in which is affixed a pin 'il projecting downwardly from said plate. Part I2; is formed with slots or grooves f8 parallel and adjacent to surfaces 26. The pins il project into the slots 13. The pins thus serve to prevent removal of part l2, and also serve to limit the inward movement of part I2` to a point where surfaces 3U, 3| thereof will be in complementary position relative to surfaces 25, 26 of body II.

Means is provided to interlock the top plate in molding position. To this end part I2 is formed with a pair of blind openings Stein the upper surfaces thereof aligned with and overlapping openings 54, in arms 52. Fixed within each opening 89 is a sleeve 8l formed with a screw threaded opening. Screwed Within each threaded opening is a hooked member 82 having a head 83 projecting rearwardly. The underedge of each of the heads 8 3 is spaced above the upper surface of member I4. lIfhe size of the head 83 is such as to permit said head to pass through slot 54. Thus member I4 may be swung downwardly to horizontal position, so that the heads 83 pass upwardly through slots 54. Each plate 'I3 is formed with a bearing opening 84. Rotatably mounted therein is av pivot pin 85. Each pivot pin 85 hasa circular head 86 at its lower end received within opening 12. It is formed with a shank 81 passing through opening 84. At its upper Aend is a polygonal head S8 spaced above' plate 13. Received on veach shank "81 and xed to the nut head 88 is a lock arm 90, 'contacting the upper surfaces of plate 13.V The lock arms'90 are adapted to be swung beneath the heads 83 of the retainer members 82 to lock the f cover or top terminal in molding position.

Although the mold is shown, for the purpose of illustration, as being adapted to mold a shoe sole, it will be understood that various other articles, such as mats, rugs, fabrics, etc., may be molded with such a mold. The shape of the cavity will, of course, depend upon the article to be molded The mold described herein is particularly useful for molding articles by use of high or radio frequency current. When the top and bot- .tom plates I 4 and I 3 are contacted with terminals ,of a high frequency current machine or apparatus, high frequency current will pass through the .rnold cavity 63. It is therefore possible to mold .in such cavities shoe soles such as shown in my Patent No. 2,361,938, dated November 7, 1944, or :any other shoe sole or other article in which a vthermoplastic or thermosetting material is to be heated for curing or plasticizing the same.

It will now be understood that the top ram provides vertical pressure, and the sliding part I2 provides lateral or side pressure. The floating bottom plate will equalize pressure in the mold. At the time of loading, the mold is flat and the bottom surface of the bottom plate is at on the loading table. The bottom plate is therefore displaced vertically up into the mold cavity. It goes down at the time the mold is released from 1oading. Then the sole will expand immediately and -the floating ramwill equalize the pressure over the bottom of the sole. The bottom plate keeps the mold cavity full and need not go down the full distance. Said floating bottom plate permits a fool-proof contact with the bus bar of a high frequency machine, such as described and shown in my co-pending application filed on even date herewith entitled Methods of and apparatus for making molded articles, Serial No. 610,261.

It is a characteristic of high frequency waves to act upand down from the positive electrode to the negative electrode, and since the mold cavity is between the two electrodes, the article to be molded receives the full current. There are no l vertical metal parts penetrating to a depth greater than the lower surface of the top ram or top surface of bottom member. The mold is easy to open and close and interlock. The necessity for preforming the sole is eliminated and hence the labor required to make the soles is cut down. Furthermore, the bottom electrode could be used to eject the sole. Preforming may be eliminated because this mold acts as a preformer, although it is understood that preforming may be employed if desired.

The locking arms 90 may be rotated by means of handles provided with socket openings to rei ceive the nuts 85. The handles may be turned in opposite directions to simultaneously open the interlocking arms.

In molding rope soles, such as shown. in my Patent No. 2,361,938, a strip of uncured rubber or thermoplastic may be placed in recess 64. The strip will become impinged upon the pins 51. During the molding operation, surface 65 will retain the rubber from owing to the side edge of the sole. Also the edge 66 serves as a cutoff to trim the outer edge of the strip. The strip is, of course, molded to the sole during the molding operation. Y

In Figs. 7, 8, 9, and 12 there is shown a mold ma embodying the invention and illustrating a nfouified construction; The mold Ita-comprises a body likewise made of ceramic material. Body 90a is of generally prismatic shape and has a top surface 9|, bottom surface 92, end surfaces 93, a front surface 94. and a rear surface 95. It is formed with a central throughropening 96, and with a slot 91 extending from the through opening 96 to the front edge 34. On each side of the slot 91 are inwardly projecting horizontal flanges 98 having inner surfaces 99 and end surfaces |00. At the lower ends of the groove are surfaces I0 I. The opening 9S comprises a vertical surface |02 which has part of the shape of a shoe sole or other article to be molded. At the other end of surface |02 is a horizontal outwardly extending surface |03. `Shouldr-:r |93 is at the level of surfaces |00. Extending upwardly from the outer edges of surfaces !03 is an upwardly and outwardly tapered surface |011 extending all around from one edge .of the groove 91 to the opposite edge.

Attached to the underside of body 90a is a plate or bottom terminal |05. Plate |05 has a portion |96 contacting the undersurface 92 of body 90a., and also adapted to be contacted by the undersurface of sliding'member |01 made of ceramic material, and slidably mounted on the body 90a in groove 91. Plate |05 is formed with an upwardly extending portion |08 projecting into the cavity |02, and having the contour of the sole or other article to be molded. rThe plate |05 is formed at the ends thereof with parallel slots |09 extending to the end edges l I0 thereof.

Means is provided for xing plate v|05 to the body 90a. To this end, the body 90 is formed with upwardly extending blind openings receiving screw threaded sleeves ||2 embedded therein by means of lead or any other suitable manner. Screwed into the threaded sleeves are screws ||3 passing through the slots |09. The slots |09`permit expansion of the plate.

Hinged to the top of body 90a is a combination cover'plate and top ram |20. The same com.. prises a top plate |2I having the general shape of a shoe sole or other article to be molded but of larger dimension. Extending rearwardly from plate |2| are parallel arms |22 hinged as at |23 to the top plate by the samehinge `means as described. above for member i4. Extending forwardly from top plate |20 are parallel arms |24 formed with longitudinal slots |25. Formed in slider |01, at points beneath the arms |24, are openings |26 in which are embedded internally screw threaded sleeves |21, Screwed within each sleeve is a latch |28. Each member |28 comprises a Screw thread |29, engaging the threads of sleeve |21, and a head |30 offset to one side and spaced above the top surface of body 90a. When the heads |30 are parallel and in alignrment with slots |25, said heads will pass through the slots. After the cover member is swung down to horizontal position, the heads |30 will be turned outwardly to the position shown in Fig. 7 to lock the cover in horizontal position.

The top cover member |20 is formed on its underside with a rarn portion |35 having the outline of the article to be molded and formed with inwardly and downwardly tapered side surfaces |36 complementary to surfaces |04. Said ram is formed on its underside all around the peripheral edge thereof with surfaces |31 adapted to contact the shoulder or surface |03.

Inwardly of vsurface |31 is a bottom surface |38 forming the top of the mold cavity. The surkface I 38 is formed around its peripheral edge,

rubber or tl'iermoplastic material to. fbe `molded to the sole. At the outer .edge of surface |31 .is a Vknife edge |39 adapted to trim the strip placed in the recess |40.

Between the topv surfaces of plate 1.0.5 and vthe undersurface of the ram |31 is a mold cavity Utl in which .the article to be molded is placed. A trade-mark stamp |43 may be embedded in the underside of the ram portion |35. The slider |01 rests on plate |05. It has a top surface |50 flush with the top surface of body 90a. It has at its sides, surfaces |5| adapted to engage the surfaces 99. It is formed with outwardly extending flanges |52 engaging the surfaces |00, |0| of the body. The slider |01 is therefore guided on the body. After the article to be molded is placed in the mold cavity, the sliding member- |01 is moved to the position shown in Fig. 10. The top plate is then moved downwardly and members |23 `turn to interlock the top plate. The top plate and bottom plate |05 may constitute terminals for molding articles by means of high frequency current.

While the molds l0 and Illa have been shown as single mold members, it is understood that the molds may have a plurality of cavities. Thus Vfor example in Fig. 13 there is shown a device Ib containing a multiple mold cavity. The device |017 may be similar to two members l0 placed rear edge to rear edge and joined. Thus member |01) is` provided with two members I4 symmetrically disposed and with two sliders |2 adapted to slide outwardly in opposite directions, Any suitable number of mold openings may be provided in the mold member.

It will be noted that the top side of sliders. :t2 as well as |01 are formed with notches |55 ,beneath the forwardly extending arms of thev top plate to permit a tool to be inserted for prying open or loosening the top plate Should it become stuck.

Preferably the top and bottom terminals, are of substantially the same thickness to. retain the heat equally above and below the mold cavity. This mold is designed for preheating Vbefore appl-ication of radio frequency and post heating after, for which reason it is desirable to. have equal heat above andl below the cavity.

In Fig. le there is shown a modied construction. In said gure |550. designates a sealingv strip to prevent leakage of rubber or .other thermoplastic material i-n the mold cavity duringv curing or molding operation. Strip. |50 may be mad-e of "Pliofilmj Korcseal or the like soft, vcompressible, impervious material having .a .melting -or fusing point above the temperatures'to; which the mold will b-e subjected.

Strips |50- are adhered tothe inner surfaces |.5I of the mold body and slider extending. all. around the mold cavity. Edge Sil of the ram 60 presses into the upper edge of the strip to prevent leakage at the top. The lower member lf3' may` .be formed with a complementary upwardlyextending peripheral edge |52 pressing against the lower edge of said spring to preventA leakage at thebottom.

Strip |59 thus prevents moldv material from flowing between the metal members 65, |3 and the ceramic body and slide.

It will thus be seen that there is providedV a device in which the several objects ofl this invention are achieved, and which is'well'- adapted to meet the conditionsof practical use.

As variousv possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is .to be understood that .all matter herein set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by ,Lettersv Patent:

l. A mold comprising a body made of electric and heat insulating material, said body being formed with a mold cavity extending to the upper surface of said mold body, said mold body being formed with a horizontal groove communicating with the mold cavity, a sliding member slidably mounted in the groove in the mold body .and made of heat and electric insulating material and adapted to close one sideof the mold cavity, a top plate hinged to the top of the mold body, said top plate and bottom plate being made of electric conducting material, and means to llock the top plate in horizontal position, and the sliding part in molding position.

2. A mold comprising a body made of electric insulating material, said body being formed with a through opening, the top of the mold body being formed with a groove extending from the top of the through opening to an edge of the mold body, a bottom plate Within the through opening, said body being formed with shoulders to support the bottom plate for sliding movement, the bottom plate constituting the bottom of the mold cavity, a sliding part made of electric insulating material, slidably mounted in said groove, a top plate provided with a ram projecting into the top of the through opening and forming the top of the mold cavity, said sliding part having a surface adapted to contact the ram, and a surface constituting a continuation of the side surface of the mold cavity, said top and bottom plates being made of electricity conducting material.

3. A mold comprising a body made of electric insulating material, said body being formed with a through opening, the top of the mold body being formed with a groove extending from the top of the through opening to an edge of the mold body, a bottom plate Within the through opening, said body being formed with shoulders to support the bottom plate for sliding movement, the bottom plate constituting the bottom of the mold cavity, a sliding part made of electricv insulating material, slidably mounted in said groove, a top plate provided with a ram projecting into. the top of the through opening and forming the top of the mold cavity, said sliding part having` a surface. adapted to contact. the ram, and a surface constituting a vcontinua-tion of the side surface of the mold. cavity, said top and bottom plates being made of electricity conducting material, said ram being formed on its underside, and around the periphery thereof, with a shallow recess to receive a stri-p'of moldable material, and cleats at the bottom of the recess on which to impinge said strip of material.

4. A mold comprising a body made of electric insulating material, said vbody being formed with .a through opening, the top ofthe mold body being formed with a groove; extending from the top of the through opening' to an edge ofthe mold body, a bottom plate within the through opening, said body' being formed with shoulders to. support the bottom plate for sliding movement, the bottom plate constituting the bottom of the mold cavity, a sliding part made r'ofi electric insulating material, slidably mountedin said groove, a top plate provided with a ram. projecting into the top of the through opening and forming the top of the mold cavity, said sliding part having a surface adapted to contact the ram, and a surface constituting a continuation of the side surface of the mold cavity, said top and bottom plates being made of electricity conducting material, said ram being formed on its underside,

and around the periphery thereof, with a shallow recess to receive a strip of moldable material, and cleats at the bottom of the recess on which to impinge said strip of material, said ram being furthermore formed at the outer edge of said recess with a downwardly projecting surface terminating in an edge to trim said strip.

5. A mold comprising a mold body, said body being formed with a mold cavity and with a groove communicating with said cavity, a sliding part within said groove being adapted to close a side of said mold cavity, a pair of plates fixed to said body and overlapping said sliding part to retain the sliding part on said body, and a top plate hinged to said body and formed with a ram adapted to project into the mold cavity, said top plate being formed with openings, hooks on said sliding part adapted to pass through said openings, and locking arms pivoted to said plates and adapted to engage said hooks to retain the top plate in locking position on said mold.

6. A mold comprising a mold body, said body being formed with a mold cavity and with a groove communicating with said cavity, a sliding part Within said groove being adapted to close a side of said mold cavity, a pair of plates fixed to said body and overlapping said sliding part to retain the sliding part on said body, and a top plate hinged to said body and formed with a ram adapted to project into the mold cavity, said top plate being formed with openings, hooks on said sliding part adapted to pass through said openings, and locking arms pivoted to said plates and adapted to engage said hooks to retain the top plate in locking position on said mold, said bottom plate being slidably mounted in the mold cavity and being adapted to project below the mold cavity.

7. A mold comprising a mold body, a bottom plate at the bottom of the mold, said mold body being formed with a mold cavity, the body being formed with a groove extending from the mold cavity to an edge of said mold body, a part slidably mounted in said groove, and adapted to close a side of the mold body, a top plate hinged to the top of the mold body and means on the sliding part to lock said top plate in molding position, said top plate being provided with a ram projecting into the mold cavity.

8. A mold comprising a mold body, a bottom plate at the bottom of the mold, said mold body being formed with a mold cavity, the body being formed with a groove extending from the mold cavity to an edge of said mold body, a part slidably mounted in said groove, and adapted to close a side of the mold body, a top plate hinged to the top of the mold body and means on the sliding part to lock said top plate in molding position, said top plate being provided with a ram projecting into the mold cavity, and means to limit sliding movement of said sliding part.

JON GREGG.

REFERENCES CITED The following references are of record in the le of this patent:

' UNITED STATES PATENTS Number Name Date 434,031 Ostrom Aug. 12, 1890 880,318 Maddox Feb. 25, 1908 1,198,874 Sloper Sept. 19, 1916 1,350,105 Maranville Aug. 17, 1920 1,594,596 Brown Aug. 3, 1926 1,964,911 Haas July 3, 1934 2,203,543 Pancorbo June 4, 1940 2,341,617 Hull Feb. 15, 1944 2,350,971 Pecker et al. June 6, 1944 FOREIGN PATENTS Number Country Date 272,419 Germany Mar. 31, 1914 

